The study reported that the institute's team had stored all 154 Shakespeare sonnets, a photo, a PDF of a scientific paper, and a 26-second sound clip from US civil rights leader Martin Luther King Jnr's "I Have a Dream" speech in a barely visible bit of DNA in a test tube.

"We downloaded the files from the web and used them to synthesise hundreds of thousands of pieces of DNA. The result looks like a tiny piece of dust," said Emily Leproust of Agilent, a biotech company that took the digital data and used it to synthesise molecules of DNA in a laboratory in the United States.

Agilent then mailed the sample across the Atlantic to the EBI, where the researchers soaked it in water to reconstitute it and used standard sequencing machines to unravel the code. They recovered and read the files with 100 per cent accuracy. "It's also incredibly small, dense and does not need any power for storage, so shipping and keeping it is easy," Goldman added.

Not great for retrieval given the high cost of synthesizing DNA, but as long-term backup, really robust.

The data stored in the test amounted to only 739 kilobytes, but the technique could be scaled up to store the three zettabytes, or 3,000 billion billion bytes, of stored data estimated to exist on earth, and the only limitation to wide implementation is the high cost of synthesising DNA, the researchers said. The world's data would theoretically fit in one hand and could be stored safely for many centuries, they said.